Immobilization of aminoacylase from Aspergillus oryzae on synthetic modified polyacrylamides

A series of acrylamide-bisacrylamide copolymers modified by the Mannich Reaction was prepared. The immobilization of aminoacylase from Aspergillus oryzae on the copolymers was studied. All the polymers adsorbed the enzyme and the activity of the immobilized enzyme dependent on the amine used, viz. secondary amine, diamine, or aniline derivative. However, the activity was also influenced by the degree of crosslinking of the polymer. The surface morphology of the dimethylamine-modified polymer, with varying degrees of crosslinking, was analyzed by scanning electron microscope; the polymers having the largest pore diameter possessed the highest enzyme activity. One of the best polymers (DMA-A9B8) was used for immobilization of aminoacylase and its properties were studied. It had high enzymatic activity and good operational stability, i.e., retaining 90% of its original activity after being used for 42 days. The use of these copolymers for the preparation of immobilized enzymes is discussed.